Actuators



Nov. 24, 1964 A. WILLIAMSON 3,158,034

ACTUATORS Filed June 28, 1962 INVENTOR Harry A. Williamson ATTORNEY United States Patent 3,158,034 AQTUATORS Harry A. Williamson, Red Bank, Ni, assignor to Electronic Associates inc, Long Branch, N.I., acorporation of New Jersey Fiied- June 28, 1962, $61. No. 266,036 9 Claims. (Cl. id-) This invention relates to actuators and more particularly toactuators for devices having plural telescoped control shafts.

Many electrical and electronic devices are reduced in size to a point where, in many instances, the size of the manually graspable actuators is a limiting factor in further size reduction or miniaturization. Heretofore, Where plural controls were mounted side-by-side, clearance between adjacent actuators had to be provided to allow for independent movement of one actuator without disturbing the setting of adjacent actuators. Telescoped shafts for piggy-back mounted devices were employed to centralize the controls and to eliminate the need for side-by-side placement of the actuators. These devices employ control knobs or actuators of the type known as co-axial. In the co-axial class of actuators, independent. knobs, usually of different diameters, are applied sequentially to the ends of the telescoped shafts. However, movement of one co-axial actuator without the disturbance of the other is virtually impossible unless great care is exercised by the operator. In some instances locks were applied to inhibit the undesired rotation of one or more adjacent actuators. These locks were complex, cumbersome and expensive. Coaxial actuators may be employed in many situations even though sufiicient room is available for side-by-side placement. As an example, they are usable where one actuator knob is connected to a coarse or range potentiometer or switch and the other knob to a fine or Vernier potentiometer. Also, they may be used in television receivers for channel selection and fine tuning. It is obvious that it is often highly desirable that the operator not disturb the setting of the fine control knob While adjusting the coarse control knob. Therefore, it is an object of this invention to provide an improved actuator which obviates the above-described difiiculties.

It is another object of this invention to provide a selectively settable actuator which inhibits accidental displacement of one knob while another knob is being positioned relative to the first.

It is a further object of this invention to provide an improved actuator for use with devices having telescoped control shafts.

The above and other objects and advantages of the invention are achieved in an illustrative embodiment of the invention described in detail below.

The illustrative embodiment of the invention will be best understood from the following description when taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a View in elevation of the illustrative embodiment of the invention, shown in a first operative position, as viewed from the plane 11 of FIG. 2 with some parts broken away and other parts in section in the interests of simplicity and clarity;

FIG. 2 is a plan view, on an enlarged scale, of the embodiment of FIG. 1 with the inner knob removed; and

FIG. 3 is a view similar toFI'G. 1, on the scale of FIG. 2, with some parts omitted and showing the illustrative embodiment in a second operative position.

The illustrative actuator 10 is shown in FIG. 1 applied to an electrical device 12 having a pair of telescoped control shafts i4, 16. Although the particular device illustrated is a piggy-back or dual potentiometer, it will be recognized by those skilled in the art that the actuator 10 is equally applicable to other devices having co-axial or telescoped shafts 14, i6.

The potentiometer 12 is secured to panel 18 by a nut 20 which engages the threaded collar 22 that is a part of the potentiometer body 24; Control shafts l4 and 16 pass through the bore of the collar 22. Wiping contact arms 26, 28 are insulated from and secured to the respective control shafts 14, 16 by conventional means. Contact arm 26, secured to the inner shaft 14, operatively engages a first potentiometer Winding 30 which is fixed in body24 of the device as by insulation 32. Contact arm 28, secured to the outer shaft 16, operatively engages a second potentiometer winding 34 fixed in the body 24 as by insulation 36. Electrical connections from the exterior of the device 12 to the wiping arms 26, 28 and to the respective windings 30, 34, not shown, are made by conventional means. In the illustrative embodiment the upper potentiometer 34 is coarse, i.e., has a greater'resistance range, compared to the lower potentiometer 30 which is the fine or Vernier potentiometer. For purposes of illustration it is assumed that the contact arm 26 is movable to an infinite number of positions throughout its 360 of rotation, while the contact arm 28 is movable through 360 of rotation only in a predetermined number of discrete steps.

An actuator body 38, preferably of metal, accommodates the outer shaft 16 in a bore 49 and is secured thereto by a set screw 42. Body 38 has a stepped recess 44 which provides clearance between the actuator and the collar 22and associated mounting nut 29. The actuator body has" a depending skirt 46 which overlies the panel 18- and to which position indicating marks or indicia may be applied. The outer periphery 48 of the body 38 has a plurality of slots or keyways 50, each having a rearwall 51, which extend vertically from the top surface 52 to the skirt 46. Additional, shorter slots 54 extend from the bottom-Wall 56 of recesses 58, formed in the periphery of the body, toward the skirt 46. The recesses 58 are deeper than the slots 50, 54 and are symmetrically disposed about the Vertical centerline of the shorter slots 54 with the rear wall 60 of the recess parallel to the rear wall 62 of the slots 54.

Retainer 64 is generally U-shaped and has a bight portion 66 which is secured to the top surface 52 of the actuator body 38 as by screws 68. The depending legs 70 of the retainer are positioned in the recesses 58. A second pair of legs 72, coplanar with bight portion 66, overlie the upper end of the longer slots 50. The bight 66 has a central aperture 74 through which the inner control shaft 14 passes.

An outer actuator knob 76, preferably of insulation, in the form of an inverted truncated cone, is slidably mounted on the actuator body 38 for relative movement therealong in a direction parallel to the longitudinal axis of the telescoped shafts 14, 16. Knob '76 has upper 78 and lower 89 planar surfaces and a central bore surface 82 which connects them. A plurality of ribs or keys 84, 86project inwardly of the bore surface 82 and are complementary to the previously described slots Stl, 54. The ribs 84, 86 are positioned in respective slots 50, 54 and are in driving engagement with the actuator body 38. Each of the ribs 84, 86 has an inner flat surface 88 which opposes the rear wall 51, 62 of the respective slots 50, 54. The clearance between the slots and ribs shown in the drawings is greatly exaggerated for purposes of clarity. Those. ribs 84 which are in the long slots 50 have a fiat upper surface 94. Those ribs 86 which cooperate with Y larly beveled. The outer periphery 98 of the actuator knob 76 extends between the top 78 and bottom 80 surfaces and has a series of longitudinally extending grooves lili) formed therein to provide a manually graspable surface.

Detent means 102 are positioned in the recesses 58 to retain the actuator knob 76 in either an extended position or a retracted position relative to the actuator body 38. The detent means 102 includes a stop member 104 which is horizontally slidable in an aperture in the depending retainer legs 79. Stop 104 has a rounded end 106 for slidable engagement with the rib surface 88. Stop collar 108 cooperates with leg 70 to limit outward movement of the stop. Stops 164 are resiliently biased against the ribs 86 by springs 110. The stop members 104 are aligned with the short slots 54 and extend beyond the back wall 62 of the slots 54.

The inner shaft 14 projects through the aperture 74 in the retainer 64 and has an inner knob 112, preferably of insulation, secured thereto as by set screw 114. Inner knob 112 has a dished upper surface 116 and a manually graspable periphery 118. The under surface 120 of the knob 112 is spaced from the upper surface 52 of the actuator body and is recessed at 122 to provide clearance for the screws 68 which fasten the retainer 64 to the actuator body. The upper surface 116 of knob 112 may be provided with position indicia. It will be recognized by those skilled in the art that the inner knob 112 may be omitted and the adjacent end of inner control shaft 14 provided directly with a manually graspable surface as by knurling.

The mode of operation of the actuator will be clear from the following description. When it is desired to adjust the fine potentiometer 30, the outer actuator knob 76 is slid downwardly along the actuator body until its bottom edge 80 abuts the skirt 46 (FIG. 1). The outer knob 76 is restrained in the retracted position by detent means 102; the stop member 104 engages the upper bevelled surface 92 of the rib 86. At this time, the inner knob 112 is readily graspable and it may be rotated to produce the desired setting of the fine potentiometer 3 1. The coarse potentiometer 34 may be set wh le the outer knob 76 is retracted by rotating the outer actuator knob 76. The ribs 84, 86 engage the slots 50, 54 so that the knob 76 is in driving engagement with the actuator body 38, to thereby provide rotation of the outer control shaft 16. The outer knob 76 may also be set while in the extended position.

In order to protect the inner knob 112 and associated potentiometer 30 against inadvertent displacement, the

outer knob 76 may be slid upwardly parallel to the longitudinal axis of the actuator body 38 until the upper surface 116 of the inner knob is substantially flush with or beneath the plane of the upper surface 78 of the outer knob 76. In this position, the outer periphery 118 of the inner knob 112 is substantially obscured or enshrouded by the outer knob 76. The diameter of the inner knob 112 is such as to allow passage of the knob 112 into the bore 82 of the outer knob to the enshrouded position shown in FIG. 3. The fiat upper surface 94 of rib 84 engages the retainer leg 72 to limit the upward movement of the outer knob 76. The outer knob 76 is retained in the extended position by the detent means 102; stops 164 are resiliently pressed against the lower bevelled surface 96 of the ribs 86 by the springs 110. In this position the possibility of accidentally disturbing the setting of the inner knob 112 while rotating the outer knob 76 is minimized but the inner knob may still be rotated as by specifically engaging its top surface 116.

It can be seen from the foregoing that the inner knob 112 is protected from disturbance during the operation of the outer knob 76 and that this is accomplished without resort to locks which must be manipulated before the rotational positions of the respective knobs 76, 112 can be changed. The detent means 102 are protected in I}. all positions of the actuator knob from accidental disengagement.

Although only one embodiment of the invention has been shown and described in detail, it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the spirit of the invention.

What is claimed is:

1. An actuator for a device having a pair of telescoped control shafts, operating means for said inner control shaft, said operating means being secured adjacent the free end of said inner shaft, an actuator body secured adjacent the free end of the outer control shaft, an actuator knob, means mounting said actuator knob on said actuator body in driving engagement with said body and for longitudinal axial movement relative to said body between a first position and a second position, said actuator knob substantially enshrouding the operating means for said inner shaft in said first position and exposing said operating means in said second position, and means for retaining said actuator knob in said first and second positions selectively.

2. An actuator for a device having a pair of telescoped control shafts, a knob secured adjacent the free end of the inner shaft for rotating said shaft, said knob having a given outer diameter, an actuator body secured to the outer control shaft, said actuator body having an outer diameter at least equal to said given diameter, an actuator knob, means mounting said actuator knob on said actuator body in driving engagement with said body and for longitudinal axial movement relative to said body between a first position and a second position, said actuator knob having an inner bore substantially encompassing the knob for said inner shaft in said first position and exposing said inner knob in said second position, and means for retaining said actuator knob in said first and second positions selectively.

3. An actuator for a device having a pair of telescoped control shafts; a first knob for operating the inner control shaft, said knob having a given outer diameter, a top surface, a bottom surface, and a manually graspable'side surface therebetween, said knob being secured adjacent one end of said inner shaft; an actuator body secured to the outer control shaft, said body having an outer diameter at least equal to the diameter of said first knob; an actuator knob having a top surface, bottom surface, a manually graspable side surface therebetween, and a central bore extending between said top surface and said bottom surface; means mounting said actuator knob on said actuator body in driving engagement with said body and for longitudinal axial movement relative to said body be tween a first position and a second position, said actuator knob accommodating said actuator body in the central bore of said actuator knob, said first knob being enshrouded by the actuator knob within said bore in said first position, said actuator knob exposing said first knob in said second position, the top surface of said first knob being substantially coplanar with the top surface of said actuator knob in said first position; and means for retaining said actuator knob in said first and second positions selectively.

4. An actuator according to claim 3 wherein the actuator knob mounting means includes a plurality of longitudinally extending keyways formed in the periphery of said actuator body and complementary ribs extending inwardly from the surface of said central bore of said actuator knob.

5. An actuator for a device having a pair of telescoped control shafts mounted for independent rotation about their longitudinal axis, the inner control shaft having operating means for rotating said shaft, an actuator body secured to the outer control shaft, an actuator knob, said actuator body and said actuator knob having complementary configurations for mounting said actuator knob on said actuator body in driving engagement for rotational movement about said longitudinal axis and for movement relative to said body along said longitudinal axis between a first position and a second position, said actuator knob substantially enshrouding the operating means of said inner shaft in said first position and exposing said operating means in said second position, and means for retaining said actuator knob in said first and second positions, selectively, said retaining means cooperating with portions of the complementary configuration of said actuator knob.

6. An actuator according to claim wherein complementary configurations of said actuator body are a plurality of peripheral longitudinally extending keyWays and said actuator knob has complementary internal keys, and said retaining means includes a stop positioned in registration with one of said keyways, and spring means resiliently biasing said stop into engagement with the respective key.

7. An actuator body for a device having a pair of telescoped inner and outer control shafts, said actuator including a first knob secured to the end of said inner shaft, said first knob having a manually engageable outer periphery whereby said knob may be rotated to drive said inner shaft, an actuator body secured to said outer shaft for rotation therewith, a second knob in driving engagement with said body, said second knob having a manually engageable outer periphery whereby said second knob may be rotated to drive said actuator body and said outer shaft, said second knob being reciprocably mounted on said actuator body for longitudinal axial movement be tween an extended position and a retracted position relative to said first knob, said second knob having portions overlying and substantially obscuring the operator engageable periphery of said first knob in said extended position, the manually engageable periphery of said first knob being accessible in the retracted position of said second knob, and detent means for retaining said second knob in either of said selected positions.

8. An actuator for a device mounted on a panel, said device having a pair of telescoped inner and outer control shafts, said actuator including a first knob secured to the end of said inner shaft, said first knob having a manually engageable outer periphery, an actuator body secured to said outer shaft, said actuator body having a skirted portion overlying said panel and a top surface spaced from said skirted portion, a second knob in driving engagement with said actuator body, said second knob having a manually engageable outer periphery whereby said second knob may be rotated to drive said actuator body and said outer shaft, said second knob being reciprocably mounted on said actuator body for longitudinal axial movement between a retracted position adjacent said skirted portion of said actuator body and an extended position remote therefrom, said second knob having portions overlying and substantially obscuring the operator engageable periphery of said first knob in said extended position, the manually engageable periphery of said first knob being accessible in the retracted position of said second knob, and detent means for retaining said second knob in either of said selected positions, said detent means being secured to the top surface of said actuator body and being concealed between said actuator body and said second knob in all positions of said second knob.

9. An actuator for a device having a pair' of telescoped inner and outer control shafts, an actuator body, having a top surface and a bottom surface, secured to said outer shaft for rotation therewith; an outer knob, means mounting said knob in driving engagement with said body, said outer knob having a manually engageable periphery whereby said knob may be rotated to drive said actuator body and said outer shaft, said outer knob being reciprocably mounted on said actuator body for longitudinal axial movement between an extended position and a retracted position; an inner knob secured to the end of said inner shaft adjacent the top surface of said actuator, said inner knob having a manually engageable outer periphery whereby said knob may be rotated to drive said inner shaft; said outer knob having portions overlying and sub stantially obscuring the operator engageable periphery of said inner knob in said extended position of said outer knob, the manually engageable periphery of said inner knob being accessible in the retracted position of said outer knob; and means for retaining said outer knob in either of said selected positions.

References Cited in the file of this patent UNITED STATES PATENTS 1,101,692 Goodspeed June 30, 1914 2,704,969 Mische Mar. 29, 1955 2,804,782 Erxleben Sept. 3, 1957 2,811,867 Hogberg Nov. 5, 1957 

1. AN ACTUATOR FOR A DEVICE HAVING A PAIR OF TELESCOPED CONTROL SHAFTS, OPERATING MEANS FOR SAID INNER CONTROL SHAFT, SAID OPERATING MEANS BEING SECURED ADJACENT THE FREE END OF SAID INNER SHAFT, AN ACTUATOR BODY SECURED ADJACENT THE FREE END OF THE OUTER CONTROL SHAFT, AN ACTUATOR KNOB, MEANS MOUNTING SAID ACTUATOR KNOB ON SAID ACTUATOR BODY IN DRIVING ENGAGEMENT WITH SAID BODY AND FOR LONGITUDINAL AXIAL MOVEMENT RELATIVE TO SAID BODY BETWEEN A FIRST POSITION AND A SECOND POSITION, SAID ACTUATOR KNOB SUBSTANTIALLY ENSHROUDING THE OPERATING MEANS FOR SAID INNER SHAFT IN SAID FIRST POSITION AND EXPOSING SAID OPERATING MEANS IN SAID SECOND POSITION, AND MEANS FOR RETAINING SAID ACTUATOR KNOB IN SAID FIRST AND SECOND POSITIONS SELECTIVELY. 